Grapes are one of the most preferred fruit species in the world. Increasing yield and quality in table grape production has always been the top priority for producers. Producers’ interest in biostimulants from sustainable agricultural practices for quality and yield increase is increasing day by day. Seaweed extracts (SWEs), which are among the most preferred biostimulants, are shown as an organic input due to their ecological safety and harmlessness. In this study, Ecklonia maxima (Em), Macrocystis integrifolia (Mi) and Ascophyllum nodosum (An), which are brown SWEs, were applied to the Alphonse Lavallée (AL) grape variety four times via the leaves. As a result of the applications, yield, quality and physiological parameters were examined. As a result of the study, all SWE applied increased yield per vine between 28% and 47%. SWEs improved cluster and berry characteristics and increased phenolic content and antioxidant activity compared to the control. They also contributed to physiological characteristics of the grapevine, such as photosynthetic activity and stomatal conductance. It is thought that SWEs, which are among the sustainable agricultural practices, will improve the yield and quality of grapes not only in organic farming but in all agricultural practices.